The Czech Republic international made a spectacular save to help keep the Premier League leaders at bay, but although he and the Blues are still in with a chance of success in both domestic and European competition, he believes this season's performances have not been up to a high enough standard.

He told the club's official website: "We are not having such a fantastic season, but this win [against Manchester United] shows we can still beat the top teams and it gives us confidence to play another game on Thursday.

"It's always important to beat big teams for the confidence. Any FA Cup progress is important for your season.

"We wanted to book a place at Wembley, we had great opposition and it was a great match. We are happy we managed to win the game.

"We seem to have a special relationship with the FA Cup. We treat it with respect, every season we try to win it and we get something back.

"We have another tough game against Manchester City, but it's a semi-final so you expect a tough game."